Release cam



May 29, 1951 c. w. MILLER RELEASE can Filed'Feb'; 2-; 1950 NVENT6%az1es' M a?! ORNE 3 Patented May 29, 1951 UNITE Appiication February2, 1950, Serial No. 141,924

This invention relates to camming mechanisms and particularly to acamming arrangement designedto effect lateral movement of a member whena second member, carrying a cam, is'moved toward or from the firstmember.

The subject matter of the present invention has particular utility inconnection with the fabricationof metal structures in punch presses.

It is often desirable, in the operation of punch presses, to performforming, piercing and trimming operations on metal by forcing a punchinto a die to'thereby shape metal placed therebetween. It is'known inthe prior art to effect transverse movement of the die member duringsome portion or-portionsof the punch stroke to further form or shape theproduct or to trim the edges thereof; In such prior art practices thedie is usually provided with cam surfaces engageable with fixed cams ona die support. After the punch has entered the die and performed apreliminary shaping operation, the die moves downwardly with the punchand the interengaging cams on the die and die support cause the dies tomove laterally of the punch to effect the desired operation. In suchprior art struc tures' the die always moves through a predeterminedcycle of lateral working movements on.

the downstroke and repeats those cycles, in

reverse, on the upstroke of the punch. The lat.-,

ter movements are non-working or idling cycles.

The present invention provides a camming,

mechanism to effect lateral cycles of movement of the dies during thedownstroke of the punch but permit the dies to remain stationary duringthe upstroke or to return to starting position at any position of thepunch.

In general, the invention comprises a pivoted cam carried by either thepunch or the die and spring-held in position to engage a cam surface onthe other member to effect lateral movements of one of the membersduring one stroke and permitting the cam to swing outwardly on theotherstroke to pass the cam surface without actuating the member uponwhich the cam surface is formed. When employed in connection with punchpress operations, the pivoted cam element may be mounted either on thedie slides or on the punch head. A special advantage of the presentarrangement resides in the fact that the same cam elements may be reusedfor different product designs, whereas the usual prior art cammingmechanism must be scrapped upon changes in product design and are notadaptable to a variety of uses.

It is, therefore; an object of this invention to claims. (Cl. 164-47provide a cammin mechanism for causing lat eral movement. of a memberwhen the cam;

ming mechanism ismoved in onedirection while ltis. a still furtherobjectof this invention to provide. a camming mechanism of the type.described that may be adapted to produce various combinations of.movementswithout modification and to eliminate the. necessity ofscrapping the cam structures for every change in the desired cycles .ofoperation. 7

it is a still further object of this invention to provide a. cammingmechanism to effect lateral movement of a member when another mem oer,carrying the camming mechanism, is caused to more inv one direction andwherein the camming mechanismis. adaptable to other members havinstrokes of different lengths.

Other objects, and advantages will become apparent to those skilled inthe art as the descriptionv proceeds; in connection with theaccompanying drawings, wherein: V r Fig. 1 is a front elevational Viewof a schematically shown punch press with a mechanism of the presentinvention attached thereto.

Fig. 2 is a side elevational view of the camming mechanism and afragmentary portion of a driven member. Y

Figs. 3 and 4 show the camming mechanism iii-different relativepositions assumed during a cycle of operation, certain parts beingomitted for clarity of illustration. Fig. 5 is a front elevational viewof the pivoted cam structure of Fig. 2,:ongitting the driven memher,when viewed from the right thereof. 4

Fig. 6 is a view similar to Fig. 3 but illustrating a modified ifOlm ofcam element. i

a Fig. Tis a front elevational view of apparatus embodying the presentinvention but adaptedto operate with a different apparatus from thatillustrated in the previous figures. A Fig. 1- illustrates arepresentation of a punch press which inciudes a suitable supportingframe it anda die supporting table l2. The frame it and table I? supportan; upwardly extending frame It to which vertical guides or tracks J5are. attached. A plunger is carries a head, 26 h vin por o s g d in thesui e a s Qr. t c

- ifitand the plunger it is'actuated by mechanisms not shown to moveupwardly and downwardly to move the head 28 toward and from the tablel2. The table i2 fixedly supports a transverse guide 22 in which a slide24 is guided for lateral movement only across the top of table I2. Theslide 24 may be provided with a vertical opening 28 therethrough inwhich a die 28 is mounted for vertical sliding movement relative to theslide 24. Suitable means (not shown) are provided for resisting downwardmovement of the die 28 and offering sufiicient resistance thereto topermit a preliminary forming operation on sheets of metal placed overthe die. The forming of the metal takes place by forcing a relativelyflat sheet into a cavity 30 of the die.

The head 28 carries a downwardly extended punch member 32 which in turncarries a punch head 34 mounted thereon for limited lateral movementrelative to the punch 32. A sheet of metal to be formed is placed acrossthe die 28 overlying the cavity 38 therein. As the plunger 18 islowered, the punch head 34 engages the metal and is of such dimensionsas to readily enter the cavity 30, forcing the metal therein and causingit to assume the shape of the cavity 30. As stated previously, means areprovided to prevent downward movement of the die 28 until the metal hasbeen forced into the cavity 38. When the metal has been forcedcompletely into the cavity 80, continued downward movement of the head28 will cause the die 28 to move downwardly therewith in the opening 25in slide 24 while the slide 24 remains vertically stationary. Duringthis continuing downward movement inter-engaging cam mechanisms causethe slide 24 to move transversely of the table I2 and since the punchhead 34 is within the cavity 3!], it will, of course, move laterallywith the slide 24 while moving downwardly in the opening 28-. Therelative positions and dimensions of the parts are such that at thattime the joint between the punch head 34 and the punch 32 issubstantially in the plane of the top surface of the die 28. Duringlateral sliding movements of the slide 24, the lowermost edge of thepunch 32 will cooperate with the upper surface of the die 28 to shearoif the upstanding edges of the sheet material. The lateral shearingoperations may be performed by elements shaped to produce other shapesthan straight lines, all as is shown in the prior art. The presentinvention is directed to a camming mechanism that may be employed forcausing lateral movements of the slide 24 on the downward stroke of thehead 28.

As shown in Fig. 1, the slide 24 is provided with a laterally projectingportion 35 having a cam surface 38 formed thereon. A camming mechanismindicated generally at 48 is fixedly carried by the head 28 and includesa cam element 52 engageable with the cam surface 38 to force the slide24 to the right as the head 28 descends.

Ordinarily, a spring, not shown, is provided to return the slide 24 tothe position of Figs. 1 and 2. However, to insure against damaging theapparatus in the event of failure of such a spring, a safety cam 3f,attached to the head 28, is arranged to engage a cam surface 33 on theslide 24 after the slide has been moved to the position of Fig. 3 tothereby insure that continued downward movement of the head 20 willreturn the slide 24 to the full-line position of Fig. 4 beforecommencement of a new cycle of operation.

Referring now particularly to Figs. 2 and 5, the cam mechanism 48comprise a base block or plate 42 that may be rigidly attached, byweldhaving aligned openings 46 therethrough. A

pivot pin 48 is mounted in the openings 46 and may be held in fixedposition therein by means such as a set screw 50 in one or both of thebrackets 44. An elongated cam element 52 is journalled on the pivot pin48 between the brackets 44 and is provided with an end cam surface 54and a notch 58 in it upper edge. A.

driver or stop means 58 is fixedly attached to the base block 42 andextends downwardly in position to engage, with intimate surface contact,a surface of the notch 58 when the parts are in the relative positionsshown in Figs. 2 and 3.. A pin 68 and a screw 62 on the cam element andbase block, respectively, constitute anchors for the opposite ends of atension spring 84. As will be readily apparent, the tension spring 54urges the cam element 52 to turn about the pivot pin 48 in acounter-clockwise direction as seen in Fig. 2 and will normally hold thecam element with its notch surface in abutting engagement with thebottom surface of the stop means or driver 58. When the parts are in thepositions shown in Figs. 2 and 3, with the cam element in abutment withthe stop means 58, the cam surface 54 of the cam element 52 is parallelto the cam surface 38 on the slide 24 and the surface 54 is directlyabove the cam surface 38 in the retracted or uppermost position of thehead 28 and the normal or central position of the slide 24.

The lowermost corner of the cam element 52 is cut away, as at 65, andthe pivot pin 48 passes through the cam element 52 on an axis displaceddownwardly from the central longitudinal axis of the cam element.

By virtue of the cut-away portion 55 and the lateral displacement of theaxis of pin 48, it will be readily apparent that the center of pressureof the surface 54 is eccentric to the end of the cam element 52, and aline such as indicated at A in Fig. 2, extending from the center ofpressure of the surface 54 to the axis of the pin 48 is notperpendicular to the surface 54 but extends therefrom at an acute angle,measured on the side of the line A opposite the side on which the stopmeans 58 and the notch 58 are located. By this arrangement it will beapparent that the reaction pressure on the cam element 52 during itsslide-driving cycles will act along line B, normal to the surface 54 atthe center of pressure, and introduce a moment tending to rotate the camelement counter-clockwise about the pivot pin 48, thus insurin thatelement 52 is held against the said stop 58.

Fig. 2 illustrates the relative positions of the cam mechanism and theslide at approximately the time when the cam element 52 engages thesurface 38. At this time the cam mechanism is moving downwardly and itwill be obvious that such downward movement, acting through the surfaces54 and 38, will cause the slide 24 to move to the right. Continueddownward movement of the cam mechanism will cause the parts to move tothe relative positions shown in Fig. 3 wherein the surface 54 has passedalmost completely oil the lowermost edge of the surface 38, forcing theslide 24 a substantial distance to the right. Continued downwardmovement of the head 20 and cam element 52 will cause the tip 10 of theelement 52 to pass completely ofi the surface 38 and ride along thevertical surface 72 of the slide 2 3. The tip 10 of the element 52 ispreferably slightly rounded, as shown, to facilitate smooth passage overthe edge of the surface 38. During movement of the tip 10 over thesurface 72, no motion is imparted to the slide 24 by that particular camelement. During this'time, however, the slide 2d may be moved to theleft by any suitable means, such as a spring or another cam mechanismsimilar to that just described but acting upon the opposite side of theslide. Fig. l illustrates the fact that the slide 2 may move to the leftfrom the dotted line position to the full line position, or farther tothe left, with no substantial resistance from the cam element 52. Duringsuch return movement of the slide 24, the cam element 52 may pivot aboutthe pivot pin 28 in a clockwise direction against only the action ofspring 6d and the notch 5% will move away from the lowermost face of thestop means 58, all as clearly illustrated in Fig. 4. The return movementof the slide 2% may be effected when the plunger i8 is at its lowermostposition or during continued downward movement of the said plunger andthe head Mi from the position of Fig. 3. Thus, a complete cycle ofoperation of the slide 24 may be accomplished during the downward strokeof the plunger and no movement will be imparted to the slide on theupward or return stroke of the plunger and head 28. During the upward orreturn stroke, the cam element 52 will freely swing to the left to clearanyobstacles or obstructions in its path and the spring 64 will returnthe element 52 to the position of Fig. 1 before commencement of the nextfollowing downward stroke.

Preferably the lowermost end of the stop means 58 is provided with aflat surface substantially normal to the direction of movementof theplunger It and engages a mating fiat surface defining an edge of thenotch 56.

Return movements of the slide 2a to the full line position of Fig. 4 andfurther movement therebeyond may, as stated previously, be accomplishedby additional camming mechanisms 69 fixed to the head 2B, but suchadditional mechanisms will necessarily be displaced from the position ofthe mechanism shown in Fig. 1 in a direction downwardly or upwardlytherefrom so that different camming mechanisms will engage the slide isin successive intervals of the downward stroke. Clearly, additionalcamming mechanisms may act on the slide 24 to cause movements in adirection transverse to that shown in Figs. 2 to 4. Movements indirections at right angles to each other may be accomplishedsimultaneously, if desired.

It will be readily apparent that instead of supporting the cammingmechanism 40 on the plunger head 20 it could, as effectively, besupported on the slide 24 and the head 20 could be provided with asuitable cam surface, corresponding to the surface 38, and theoperations described above would result since they depend merely uponrelative movement of the head 20 and the slide 24.

In addition to the modification suggested in the paragraph above, theparts may be so arranged that the slide 24 is caused to move verticallywith the die member 28, in which case the surfaces 38 and 33 would facedownwardly and the camming mechanism 40 would be fixed to the table l2in an inverted position. Thus relative movement between the slide 24 andthe table l2, in a downward direction, would result in the sametransverse movement of the slide 24;

Fig. 6 illustrates a modified form of cam element 52' wherein the camsurface engaging means comprises a roller 14 journalled to the end ofthe element 52 on an axis parallel to the axis of pivot pin 48. Thepoint of contact between the roller 74 and the surface 38 is displacedlaterally of the element 52 in the same manner and for the same purposeas described in connection with the lateral displacement of the centerof pressure of the surface 54 of the Fig. 2 embodiment. A line Aextending from the axis of the pivot pin 48 to the point of contactbetweenthe roller 7A and the surface 38 extends from the said surface atan acute angle measured on the side of the line opposite the stop means58. In the same manner as described in connection with Fig. 2, thereaction pressure exerted by the surface 38 on the element 52 will actalong the line indicated at B to hold the element 52 firmly against thestop means 558 during all slide-actuating cycles.

The camming mechanism herein described may obviously be employed whenproducing a diverse variety of shapes involving the use of differentpunch and die members without alteration of the camming mechanismstructure. At most, only repositioning thereof will be necessary. Upon achange in the design of the article to be produced, the present cammingmechanism need not be scrapped, as is the case with known cammingstructures of the prior art. If a different shape of cam element 52 isrequired, it is only necessary to loosen set screws 58 and remove pivotpin 88, whereupon a differently shaped cam element may be inserted.

In the modification shown in Fig. 7, all parts identical to those of thepreviously described embodiments are identified by the same referencenumerals. In this modification, however, a different type of die is usedto perform a somewhat different operation than that described above. Asupport MB is mounted upon the table 52 and provided with a shoulder I92defining a relatively sharp edge at its exterior periphery and anupstanding positioning member Hit. The positioning member Hi l isarranged to support and position a work piece it thereon with a scrapedge portion H38 extending outwardly over the edge I02. The work pieceHi5 will have been formed by a previous operation on another machine.One side of the member file-i515 is provided with a cut-out i it of suchcontour as to present the desired outline to the outer periphery of theportion m l. Suitable guiding means H2 are fixed to the table l2 andguide a punch carrier li t for rectilinear movement toward and from thesupport mil. The punch carrier I It carries a laterally extending punchi H3 of a size and shape complementary to the cut-out Ill) and is alsoprovided with inclined cam surfaces H8 and i221. A camming mechanism6'3, identical to that previously described, is mounted on a block E22fixed to the head 28 in such position that it engages the cam surface M8on the carrier M4 to force the carrier lid to the left as seen in Fig. 7upon downward movement of the head 26 to thereby cause the punch H6 toperforate or out the work piece it to a shape determined by the contourof the punch HS and the cut-out lit. The cam surface iZti on the carrierH4 cooperates with a safety cam I24 in exactly the same manner describedin connection with the safety cam 3I and surface 33 of Fig. 1.

A die member I30 is fixed to the head 20 which die member is providedwith a bore I32 defining a peripheral wall having a relatively sharpinner edge corner I34 of such shape and configuration as to receive themember I therein with only shear clearance between the edges I34 andI02. Upon downward movement of the head 20 to its lowermost position itwill be apparent that the edges I02 and I34 will cooperate to shear thewaste material I08 from the work piece I06.

During operation of the device shown in Fig. 7, downward movement of thehead 20 from the position shown will first cause the carrier H4 andpunch lit to move inwardly and perforate the work piece. As soon as thecamming mechanism 50 reaches a position comparable to that shown in Fig.4 of the drawings, a spring or other suitable means (not shown) returnsthe slide a outwardly to its starting position as suggested by the fullline of Fig. 4. In the event of failure of such spring, the safety camI24 cooperating with the surface I20 insures return of the carrier to aposition where the end of the punch H6 is clear of the path of movementof the die I30. Lateral perforation of the work piece and return of thecarrier to its outermost position is accomplished before the lowermostend of the die I30 reaches the top of the punch II5 so that continueddownward movement of the head 23 will have no further effect on thecarrier H4 but will cause the die I30 to shear the waste material fromthe work piece. During the upward stroke of the head 20 the cammingmechanism 40 will be merely withdrawn and the arm 52 thereof will bepermitted to return to the position of Figs. 1 and 2 relative to therest of the camming mechanism. After completion of each cycle ofoperation, the trimmed work piece I06 may be removed and a new workpiece placed upon the support I30.

The camming mechanism of the presentinvention has been described inconnection with a metal fabricating punch press merely for purpose ofillustration and it will be obvious that the mechanism may be employedin many other machines without departing from the spirit of the presentinvention.

A limited number of specific embodiments have been described herein butit is to be understood that the invention is not limited thereto, suchdescription being merely illustrative. The invention disclosed herein isto be limited only by the scope of the appended claims.

I claim:

l. A camming mechanism comprising, a pair of members relatively movablealong a predetermined rectilinear path, one of said members beingmounted for independent rectilinear movement transversely of said path,a certain one of said members being provided with a cam surface, theothe of said members carrying a cam mechanism having a cam elementmovable into engagement with said cam surface when said members arerelatively moved along said path, to effect transverse movement of saidone of said members, said cam element beingpivotally mounted on saidmechanism, stop means on said mechanism, resilient means urging saidpivoted cam element into engagement with said stop means, said stopmeans being so positioned as to prevent pivotal movement of said camelement away from said .cam surface when said element is in drivingengagementwith said surface, said cam surface being fiat and extendingdiagonally of said path and said cam element being provided with a fiatsurface for engaging said cam surface, said flat surface being parallelto said cam surface when said cam element engages said stop means, thearrangement being such that a line from the pivotal axis of said camelement to the center of said flat surface forms an acute angle withsaid surface on the side of said line opposite said stop means.

2. A mechanism as defined in claim 1 wherein said stop means and saidcam element are provided with mating fiat surfaces substantially normalto said path when said surfaces are in engagement with each other.

3. A camming mechanism comprising, a pair of members relatively movablealong one path and relatively movable along another path transverse tosaid one path, one of said members having a cam surface thereonextending diagonally of said one path and said other path, an elongatedcam element pivoted adjacent one end thereof to the other of saidmembers on an axis substantially normal to both said paths, cam surfaceengaging means at the other end of said cam element, stop means on saidother member, resilient means pivotally urging said cam element intoengagement with said stop means, said cam element engaging said stopmeans when said cam element lies nearly perpendicular to said camsurface.

4. A mechanism as defined in claim 3 wherein said parts are so arrangedthat said stop means prevents pivotal movement of said cam element awayfrom said cam surface when said element engages said cam surface duringmovement of said members in one direction along said one path wherebysaid cam element will be effective to move said one member in onedirection along said other path.

5. A mechanism as defined in claim 3 wherein a line extending from thecenter of contact between said cam element and said cam surface to thesaid axis is oblique to said cam surface.

6. A mechanism as defined in claim 3 wherein the center of contact ofthe said cam surface engaging means at the said one end of the camelement is transversely displaced from a radial line extending from saidaxis normal to said cam surface, said displacement being in a directiontoward said stop means.

7. A mechanism as defined in claim 3 wherein the cam surface engagingmeans of said element is a fixed surface parallel to said cam surfacewhen said element is in engagement with said stop means.

8. A mechanism as defined in claim 3 wherein the cam surface engagingmeans of said element comprises a roller journalled to said cam elementat the said other end thereof.

9. A camming mechanism comprising, a pair of members relatively movablealong one path and relatively movable along another path transverse tosaid one path, one of said members having a cam surface thereonextending diagonally of said one path and said other path, an elongatedcam element pivoted adjacent one end thereof to the other of saidmembers on an axis substantially normal to both said paths, cam surfaceengaging means at the other end of said cam element, the arrangementbeing such that when said engaging means of said element engages saidcam surface a line normal to said cam surface and passing through thecenter of pressure of said cam surface engaging means passes to one sideof said pivotal axis, stop means carried by said other member on saidone side of said axis and in position to engage said element and limitpivotal movement thereof about said axis, and yieldable means urgingsaid element toward said stop means.

10. In a punch press having a plunger movable toward and from a diealong a predetermined path, said die being mounted for independentmovement transversely of said path and being provided with a camsurface, the said plunger carryinga cam mechanism having a cam elementmovable into engagement with said cam surface when said plunger is movedalong said path in one direction, to effect transverse movement of saiddie in a first direction, said cam element being pivotally mounted onsaid mechanism, stop means on said mechanism, resilient means urgingsaid pivoted cam element into engagement with said stop means, said stopmeans being so positioned as to prevent pivotal movement of said camelement away from said cam surface when said element is in drivingengagement with said REFERENCES CITED The following references are ofrecord in the file of this patent UNITED STATES PATENTS Number Name Date1,717,612 McNeil June 18, 1929 1,848,201 Rook Mar. 8, 1932 20 2,507,637Krize May 16, 1950 FOREIGN PATENTS Number Country Date 836,683 FranceJan. 24, 1939

